Published every four years, the report from the National Intelligence Council (NIC) aims to draw together a wide sweep of "megatrends" driving transformation in the world.

'Slow relative decline'

The NIC suggests that by 2030, Asia will have more "overall power" than the US and Europe combined - taking into account population size, gross domestic product (GDP), military spending and investment in technology.

"China alone will probably have the largest economy, surpassing that of the United States a few years before 2030," the report says.

"Meanwhile, the economies of Europe, Japan, and Russia are likely to continue their slow relative declines."

But the report says it does not anticipate that China will emerge as a superpower in the mould of the US, forging coalitions to take on international issues.

Speaking at a news briefing, Mathew Burrows, counsellor to the National Intelligence Council said: "Being the largest economic power is important... [but] it isn't necessarily the largest economic power that always is going to be the superpower."

Looks like Paul Kennedy has become popular at the NIC once again. No doubt the neocons are screaming about this return in declinist thinking. Kennedy's thesis is often overstated - the largest economy, all other things being equal, allows a nation to win a war. Institutional international arrangements, military training, technology and alliances will still favour the US for a while - it's the obvious fact that America built the post-WWII international system which means that system will benefit it even while it fails to be the largest economic power, as Fukuyama belatedly realized after a decade of drinking neocon kool aid.

But still, in the long run, it does suggest a sizeable power shift towards the Pacific, as people were discussing before the "New American Century" "hyper-power" bullshit of 2002-5.